Tips and Tricks for Dell PSU Replacement
I worked as an onsite technician for Dell for awhile, doing ten service calls per day on average. So, trust me, I've replaced a lot of power supplies. Here are some precious gems I picked up along the way:
Have Band-Aids Handy - The insides of Dell machines aren't "flesh friendly." There are lots of sharp edges, and getting nicked, scraped, or cut should be expected. I'd almost go as far as to say that you should wear gloves unless you're like me and just don't care.
Screws AND Levers - Dell likes to make sure that nothing inside their desktop PCs moves around - not ever. So expect the power supply to be screwed down in multiple places as well as to have some kind of latch or lever that also holds it in place should all six or so screws simlutaneously fail (I wish C-3PO was here to tell me the likelihood of something like that ever happening). You may also have to contend with proprietary mounting brackets. In fact, count on it. The vast majority of Dell desktops have power supplies that are screwed to a mounting bracket, which is then latched and screwed onto the chassis. To replace them, you'll have to remove the bracket and put it on the new Power Supply before installing it in the case.
How Do I Even Open This Thing - Dell desktops often remind me of puzzle boxes. Which buttons do I have to simultaneously press while nudging this panel to get this thing to crack open? Logic dictates that there will be one panel that slides off, revealing the insides---and that is true of most non-Dell computers. However, count on your Dell to have some strange configuration that combines levers, buttons, sliding, tilting, and rotating to open up. If you get lost, search the net for your specific Dell model, and you should find instructions.
And Don't Forget the Zip Ties - Dell also likes zip ties---a lot. Most of the wires running from the power supply to various locations in the computer will be clipped or zip-tied down in places. You may even find that the wires run along the bottom of the chassis, underneath the motherboard. This means that you would actually have to completely remove the motherboard to even get the power supply out. If you find this to be the case, do yourself a favor and consult a professional.